A bipolar battery is a battery constructed with a plurality of bipolar electrodes, and has excellent properties, such as light, thin, and preferable heat radiation.
When a bipolar battery is used as a source of power for a vehicle, reliability and stability are required. If the charging capacity of a plurality of electric cells of the bipolar batteries (an electric cell is developed between each of the bipolar electrodes) differs, the required output performance and capacity performance cannot be given. Therefore, the charged conditions of each electric cell need to be equally maintained at all times.
For that purpose, a charge and discharge system of each electric cell is controlled individually by connecting a voltage detecting wire (used for detecting voltage of an electric cell) and a bypass wire (used for bypassing an electric cell) for each electric cell. The connection of the bypass wire is controlled depending on the voltage detected by the voltage connection wires.
However, voltage detecting wires and bypass wires are undesirable in that the voltage detecting wires and bypass wires have to be drawn from each current collector provided between the bipolar electrodes, which often requires long man-hours. Moreover, sealability of the sheathing materials has to be ensured.